Redesign of an assembly line and application of rabit chasing assembly method

As a result of the increasing of the competition and market expansion, companies have to adjust their production as well as reduce costs and raise the quality of the targets according to continuous variable customer demands The flexible and hybrid line which has automation system was redesigned against of this variable customer demands to be able to answer by adjusting the number of employees It is called that rabit chasing production method which is by walking operators around in line with parts, perform each task in sequence and follow each other was recommended. This study has 6 chapter by starting with "Lean manufacturing and Value Stream Management" and ending "Results and Recommendations" In the chapter of "Lean manufacturing and Value Stream Management", there are descriptions about Lean manufacturing wastes (overproduction, transportation, inventory, non-quality or rework, waitings, unnecessary motions, overprocessing) material and information flow systems. These material and information systems have been classified according to material flow. In the second chapter of "introduction to assembly line design ", The basic concepts related to assembly line informations and concept for performance in the assembly line, balancing of the assembly lines and balancing types (horizantal and vertical balancing), classification of the assemby lines, the notions related to the number of models and ranking (one model lines, multiple model lines and mixed model lines) material handling systems between assembly line stations (non-mechanical lines and moving band lines) was explained with details. Furthermore, the assembly lines have been classified and explained with details related to U line and the straight lines In the third chapter, there is current literature information related to the subject, including an explanation and summary of the literature matrix. Literature matrix for assembly line balancing at table 1 was classifed in terms of line spesifications (Single model deterministic, single model stokastic, mixed model deterministic, mixed model stokastic and other spesifications), the type of line (straight line and U type line) the aim (cycle time minimization, station minimization, operator cost minimization, equipment cost minimization,total cost minimization, line efficiency maximization, idle time minimization, work load smoothing and others). Literature matrix for assembly line balancing at table 2 was classifed according to teams (team oriented assembly lines or not), vertical and horizantal balancing, method used (heuristic algorithm, optimization and other heuristics) parelel stations, sequencing in additions to balancing, assignment method of operators (assigned or not), real life applications (This study can be applicated to real life or not). In the fourth chapter, the rabit chasing production method and developed methodology has been explained with details. The importance of this method has been highlighted and the advantages and disadvantages of rabit chasing production method have been explained. In chapter 5, "An application at assembly production system", the information of company and assembly line where application was made has been presented and the exist situation analyze and then improved or future situation analyze has been made. According to the future situation analyse, the actions and suggestions have been determined for the removing wastes at the all company process including assembly lines. These results was demonstrated by charts and images, the production system was simulated and tested by using a simulation Arena program and the result of this study was shared. This study presents a new methodology related to redesign of an assembly line and application of rabit chasing assembly method. This methodology consist of eleven steps and it was applicated at the clutch production assembly line. Firstly takt time according to customer order and production parameters were determined and then the current state value stream anlayse was established. After the target stock times were defined for each production units, the root cause analyse (5 why analyse) of over stocks between production units was made for reach of the target stock times. Likewise the root cause analyse (5 why analyse) was conducted to reduce cycle time at the workshop. Then the future state value stream analyse which is consist of countermeasures was created. Afterwards, two investment alternatives were investigated (one of the new pres and automation system and the other alternative is removing complete assembly station and buying a new rotatary automatic machine with crushing operation by including some complete assembly operation tasks.), benefit and cost analyse of them was made and the investment requirement was defined. The alternative of new press with automation system at the first station has been decided and other is eliminated according to this investment analyse. The number of target operator was calculated at the new situation cycle time diagram. The accuracy of the target number of employees and work methods of them has also been tested by using simulation program. Work process improvement actions for the necessary number of employees have been decided at the last phase of methodology. The last chapter has conclucions of the study and recommendations about another research to be pursued in the future. According to conclusions, the scenario of totaly four operators in the rabit chase production method was concluded that the most proper option when taken additional costs into account for five operators in terms of indicators such as cycle time, lead time, the average machine utilization percantage, production pieces and the average number of waiting parts at the bottleneck station's queue. The number of four operator working production method was also found according to new situation cycle time diagram result . In the future, mathematical models can be done with details and the quality problems can be added to analyse, studies on product size can be put forward, heuristic methods can be conducted and developed, besides these considerations the learning curve of operators can be considered and as well as, the surface methodology can be examined to analyse, furthermore at the end of study, how the accurate results can be ensured has been stated.